1. Field of the Invention
This invention relates to building wall structures, and more particularly to blow-in/blow-out wall structures adapted to collapse inwardly or outwardly relative to the building framework when acted upon by abnormally high positive or negative wind pressures.
2. Description of the Prior Art
In the past, building wall structures have been adapted to be separated from the structural framework -- usually away from the framework -- when the wall structure experiences a selected elevated pressure. Such elevated pressures may be created by explosions occurring within the confines of the building or by abnormally high negative wind pressures.
Such wall structures have been provided with panels or panel portions held in place by resilient members. See for example U.S. Pat. Nos. 3,112,535; 3,150,749; 3,258,890.
In another arrangement, the wall panels are provided with clip angles which are secured to the frame members by releasable fastening means, such as fasteners of the type which will fail in shear or in tension. See for example U.S. Pat. No. 3,258,887.
In still another arrangement, the wall panels are secured to the structural framework by pressure release fasteners which incorporate a deformable metal washer which is forced over the fastener head during release of the panel. See for example U.S. Pat. No. 3,828,493.
Blow-out roof structures also are known which incorporate flat metal sheets having their entire peripheral edge releasably clamped to supporting structure, see for example U.S. Pat. No. 3,363,376. In another blow-out roof structure, roof sheets are connected by pre-bent sheets adapted to be deformed by explosive pressures within the separator, and wherein the peripheral edges of the roof structure are releasably clamped to the supporting structure, see U.S. Pat. No. 3,386,215.